Hare’s Electrical Plate Machine. 199 
My plate (thirty-four inches in diameter) is supported 
upon an upright iron bar, about an inch in diameter, cover- 
ed by a very stout glass cylinder, four inches and a half in 
diameter, and sixteen inches in height, open only at the 
base, through which the bar is introduced, so as to form its 
axis. The summit of the bar is furnished with a block of 
wood, turned to fit the cavity formed at the apex of the cy- 
linder, and cemented therein. The external apex of the 
cylinder is cemented into a brass cap, which carries the 
plate. The glass cylinder is liable to no strain; it is only 
pressed where it is interposed between the block of wood 
Within, and the brass cap without. The remaining portion 
of the cylinder bears only its own weight, while it effectu- 
ally insulates the plate from the iron axis. The brass cap 
is surmounted by a screw and flange ; by means of which, a 
corresponding nut, and disks of cork, the plate is fastened. 
A square table serves as a basis for the whole. The iron 
axis, passing through the cover of the table, is furnished 
with a wooden wheel of about twenty inches diameter, and 
terminates below this wheel in a brass step, suppor 
cross of wood, which ties the legs of the table diagonally 
together. The wheel is grooved, and made to revolve by a 
may of course be turned by means either of one or both. It 
'8 supported on two strips of wood, which, by means of 
Acrews, may be protruded, lengthwise, from cases, which 
confine them from moving in any other direction. By 
these means, the distance between the wheels may be va- 
tied at pleasure, and the tension of the band duly ad- 
Justed. 
suspended upon wooden axes, surmounted by plugs of cork, 
turned pabsantaty to fit the space which they nenin jhe 
cylinders are kept steady, below, by bosses of wood, w 
